Apesar da importância dos herbívoros de solo na estruturação da comunidade e também como pragas agrícolas, nosso entendimento sobre a ecologia química de suas interações com a planta hospedeira é limitado comparado à vasta literatura sobre os herbívoros que se alimentam de órgãos aéreos das plantas. O presente estudo teve como objetivo identificar os estímulos olfativos envolvidos na busca hospedeira de Diabrotica speciosa. Larvas de 1º. ínstar de D. speciosa foram capazes de localizar plantas hospedeiras de milho, mas sem distinguir plantas não induzidas das induzidas pela herbivoria radicular e/ou foliar. Já larvas de 2º e 3º ínstar apresentaram preferência por plantas sem indução frente a plantas induzidas pela herbivoria radicular. No entanto, estas larvas preferiram plantas induzidas pela herbivoria foliar em detrimento a plantas sem indução. Na situação em que plantas sem indução foram confrontadas com plantas induzidas pela herbivoria foliar + radicular não houve preferência destas larvas. A análise do perfil de voláteis juntamente com o PCA (\'Análise dos Componentes Principais\') revelaram semelhança entre os voláteis emitidos por plantas induzidas pela herbivoria radicular e foliar + radicular, bem como entre plantas sem indução e induzidas pela herbivoria foliar. Estas diferenças nos perfis de voláteis não foram suficientes para explicar o comportamento de busca hospedeira de larvas de 2º e 3º ínstar, sugerindo a possibilidade de outras pistas químicas associadas com a busca hospedeira de larvas de D. speciosa. / Despite the importance of soil herbivores in community structure and their status as pests, our understanding about the chemical ecology of their interactions is still limited compared to the vast literature on aboveground herbivores. The current study aimed at identifying the olfactory stimuli used in host search by Diabrotica speciosa. First-instar larvae of D. speciosa were able to find corn host plants; however, they did not distinguish between herbivore-induced and non-induced plants (control). Second-and-third-instar larvae preferred non-induced over root-herbivore induced plants. Nevertheless, second-and-third-instar larvae preferred leaf-herbivore induced plants, inflicted by D. speciosa adults, over non-induced plants. When larvae were exposed to non-induced and leaf + root-herbivore induced plants, they did not show preference. Volatile profile analysis together with PCA (Principal Component Analysis) revealed similarity between volatiles emitted by root-herbivore induced and leaf + root-herbivore induced plants as well as between non-induced and leaf-herbivore induced plants. These differences in plant volatile profile were not sufficient to explain host search behavior of second-and-third instar larvae, suggesting the possibility of other chemical cues are associated with host search of D. speciosa larvae.

Esta dissertação teve como objetivo geral ampliar o conhecimento sobre a ecologia vegetal das matas de Restinga arenosa em substratos bem drenados no Rio Grande do Sul. Para tanto, foram realizados o estudo florístico e fitossociológico do componente arbóreo de cinco capões de Restinga e a verificação de padrões de interações mutualísticas entre aves frugívoras e as árvores, além do estudo do componente de regeneração e suas relações com o estrato arbóreo adulto. Para a amostragem da vegetação, foi usado o método de parcelas, incluindo-se todas as árvores com DAP ≥ 5cm, totalizando uma área de 1,02ha. Com estes dados, foram estimados os parâmetros usuais em fitossociologia. Em um dos capões, foi realizado também o levantamento florístico e fitossociológico das plântulas (0,05 ≤ altura < 1m) e juvenis (altura ≥ 1m, DAP < 5cm), avaliando-se as relações com o estrato arbóreo adulto, o potencial e a taxa de regeneração natural para cada espécie. Para o estudo dos mutualismos, foram feitas observações visuais e capturas de aves durante um ano. Foram estimadas a conectância do sistema mutualístico e o índice de importância das espécies. Também foi feita a rede de interações do sistema e feita a análise da variação destas interações ao longo das estações do ano. A composição florística resultou em uma riqueza total de 20 famílias e 29 espécies para os cinco capões. A densidade total arbórea teve uma média máxima de 1207 ind/ha e mínima de 747 ind/ha. Sebastiania serrata apresentou o maior valor de importância e Myrtaceae foi a família mais representada. A diversidade específica foi baixa, variando de 1,08 a 2,38 (nats). No sistema mutualístico, registraram-se 29 espécies interagindo (aves e plantas), com uma conectância de 23,9%. Turdus amaurochalinus e T. rufiventris interagiram com a maioria das espécies arbóreas e tiveram o maior índice de importância, sendo caracterizadas como as principais dispersoras em potencial. Ocotea pulchella e Myrsine spp. foram registradas com maior número de eventos de consumo de frutos, no entanto, Ficus organesis interagiu com mais espécies frugívoras, além de ter a maior importância na dieta das aves. Houve variações no número eventos de frugivoria ao longo das estações, bem como no número de espécies frugívoras e de espécies arbóreas consumidas. O componente de regeneração apresentou riqueza específica e diversidade semelhantes às do estrato arbóreo adulto, refletindo uma similaridade florística maior que 70%. A maioria das espécies (73,7%) apresentou taxa de regeneração negativa, revelando o padrão de 'J' invertido. Os resultados indicam a existência de diferenças na composição e estrutura arbórea entre os capões de Restinga, além de uma boa capacidade de regeneração para a maioria das espécies vegetais estudadas. Os dados revelam também um sistema dispersão generalista, no qual poucas espécies de aves interagem com muitas espécies arbóreas e vice-versa. / This dissertation had as broad objective the knowledge amplification about the plant ecology of sandy Restinga forests in well drained soils in Rio Grande do Sul. For that, the floristic and phytosociological study of the tree component of five Restinga woods and the verification of mutualistic interactions patterns between frugivorous birds and trees were accomplished, besides the study of the regeneration component and its relations with the adult tree stratum. For vegetation sampling, the plot method was used, including all trees with DBH ≥ 5cm, totaling an area of 1,02ha. With these data, the usual parameters in phytosociology were estimated. In one of the woods, the floristic and phytosociological survey of the seedlings (0,05 ≤ height < 1m) and juveniles (height ≥ 1m, DBH < 5cm) was also performed, evaluating the relations with the adult tree stratum, the potential and the rate of natural regeneration for each species. For the mutualisms study, visual observations and bird captures were done throughout one year. The connectance of the mutualistic system and the species importance index were estimated. The interactions system network and the variation analysis of these interactions throughout the seasons were also done. The floristic composition resulted in a total richness of 20 families and 29 species for the five woods. The total tree density had a maximum media of 1207 ind/ha and a minimum of 747 ind/ha. Sebastiania serrata presented the highest importance value and Myrtaceae was the most represented family. The specific diversity was low, varying from 1,08 to 2,38 (nats). In the mutualistic system, 29 species interacting (birds and plants) were registered, with a connectance of 23,9%. Turdus amaurochalinus and T. rufiventris interacted with most tree species and had the highest importance index, being characterized as the main potential dispersers. Ocotea pulchella and Myrsine spp. were registered with the higher number of consumption events, although, Ficus organesis interacted with more frugivorous species, besides having the higher importance in the birds diet. There were variations in the frugivory events number throughout the seasons, as well as in the number of frugivorous species and consumed tree species. The regenerating component presented specific richness and diversity similar with the adult tree stratum, reflecting a floristic similarity higher than 70%. Most species (73,7%) presented negative regeneration rates, revealing the inverted 'J' pattern. The results point to the existence of differences in the forests tree composition and structure among the Restinga woods, besides a good regeneration capacity for most plant species studied. The data also reveal a generalist dispersal system, in which few bird species interact with many tree species and vice-versa.

Among the number of examples of broad radiations of insects on plants, the fig fig wasp system is one of the most remarkable. Although this interaction has frequently been used as a model for studies of mutualism and coevolution, other groups of insects associated with fig trees have received less attention. The weevils (Coleoptera: Curculionidae) associated with figs are one notable example. Being the largest family of animals, weevils achieved great evolutionary success due to their early association with their host plants. Despite few reports in literature, there is strong evidence of the specialization of weevils on figs. The main objective of this thesis was to understand how diversification of Curculionidae took place in fig trees. Previous studies have never addressed the systematics and biogeography of fig weevils under a phylogenetic framework. Therefore, we analyzed the tempo of diversification of Curculionidae lineages that use fig trees as host in order to reconstruct their historical biogeography. To gather information on fig weevils, we collected 325 fruit sets from more than 12% of the total Ficus species, from the Neotropical, Afrotropical and Oriental regions. We also examined seven entomological collections (AMNH, BMNH, INBIO, MNHN, MZUSP, NMNH, SAMC) searching for weevil specimens collected on figs. At least 80 weevil species from five genera (Cetatopus, Omophorus, Carponinus, Curculio, and Indocurculio) were found to be associated with figs. The radiation of curculionids on figs occurred at least three times independently. The tempo of diversification of the crown fig weevils is congruent with the diversification of figs during the Upper-Cretaceous/Lower-Eocene period. We hypothesize that the variation of the sea level and warmer climate in the past had great influence on the evolution of the species. Our results encourage future research on the biology and ecology of these species and will help us to understand the role weevils may have played in the evolution of the fig- fig wasp mutualism. / Um dos mais notáveis exemplos de radiação adaptativa de insetos em classes de plantas é o sistema figueiras - vespas de figo. Embora essa interação tenha sido frequentemente usada como modelo nos estudos de mutualismo e coevolução, outros grupos de insetos relacionados às figueiras têm sido negligenciados. Besouros curculionídeos (Coleoptera: Curculionidae) associados a figueiras representam um desses grupos pouco estudados. Apesar dos relatos escassos na literatura, existem fortes evidências do alto grau de especialização destes besouros às suas plantas hospedeiras. O objetivo geral desta tese foi entender como se deu a diversificação dos curculionídeos sobre as figueiras. Trabalhos anteriores nunca utilizaram uma abordagem filogenética para estudar a sistemática e biogeografia dos curculionídeos de figo e, por isso, este estudo analisa o tempo de diversificação das linhagenes destes besouros para reconstruir sua biogeografia histórica. De modo a obter informações das espécies estudadas, foram coletadas 325 amostras de frutos de cerca de 12% do total de espécies de figueiras das regiões Neotropical, Afrotropical e Oriental. Sete coleções entomológicas (AMNH, BMNH, INBIO, MNHN, MZUSP, NMNH, SAMC) foram vistadas em busca de espécimes de curculionídeos coletados em figo. Pelo menos 80 espécies de cinco gêneros (Cetatopus, Omophorus, Carponinus, Curculio e Indocurculio) foram encontradas. A radiação dos curculionídeos de figo ocorreu independentemente pelo menos três vezes ao longo da história dos Curculionidae. O período de diversificação das linhagenes de curculionídeos de figo é fortemente congruente com o período de diversificação das linhagenes de figueiras durante o fim do Cretáceo/Paleoceno. Acredita-se que fatores como a forte variação no nível dos oceanos e o clima mais quente no passado tiveram grande influência na evolução das espécies. Espera-se que os resultados deste trabalho encorajem estudos futuros sobre a biologia e ecologia dos curculionídeos associados às figueiras e auxilie no entendimento do papel que os curculionídeos possam ter desempenhado na evolução do sistema Ficus - vespas de figo.

O Fusarium spp. é um fungo cosmopolita, compreendendo uma grande quantidade de espécies que são conhecidas por causar doenças em culturas de importância agronômica. Embora, isolados não patogênicos de Fusarium spp. tenham sido descritos, pouco se conhece sobre a variabilidade genética deste grupo, ainda que estejam presentes em inúmeros locais. Assim sendo, este trabalho teve como objetivos ampliar estes conhecimentos, avaliando a variabilidade genética e forma de interação de isolados patogênicos e não patogênicos de Fusarium spp. obtidos de diferentes hospedeiros. Desta forma, 83 isolados de Fusarium spp. foram avaliados por meio das técnicas de ARDRA, sequenciamento do rDNA e RAPD. A análise por meio de ARDRA, permitiu a distinção dos 83 isolados de Fusarium spp. em 19 haplótipos, apresentando uma grande diversidade dentro de cada haplótipo, mas de forma geral os isolados patogênicos e não patogênicos de Fusarium spp. não puderam ser discriminados. Nas análises de sequenciamento da região ITS do rDNA, foi observado que isolados de Fusarium se agruparam independentemente da espécie. Estes resultados comprovam a necessidade de uma revisão taxonômica dentro do gênero Fusarium. A análises por marcadores RAPD revelou que os 83 isolados de Fusarium spp. avaliados neste estudo apresentaram ampla variabilidade a qual não está correlacionada com a característica taxonômica. Entretanto, foi observado que isolados patogênicos e endofíticos de F. oxysporum obtidos de soja são geneticamente diferentes. Quanto às análises de interação de isolados patogênicos e não patogênicos de Fusarium spp. com cultivares susceptíveis de tomate e soja, verificou-se que estes isolados interagiram de forma diversa, nos diferentes tecidos vegetais, sendo que alguns isolados endofíticos promoveram o crescimento vegetal. Dentre estes, destaca-se o isolado endofítico Cac19.4 que mostrou-se geneticamente diferente de isolados patogênicos de Fusarium spp., além de promover um aumento de peso da raiz e caule de plântulas de soja e tomate. Dessa forma este isolado poderia ser selecionado para futuras análises, visando um melhor aproveitamento deste microrganismo endofítico em estudos de interesse agronômico. / Fusarium spp. is a cosmopolitan fungus that covers a great number of species known by the ability of causing diseases in agricultural important crops. Although non-pathogenic isolates of Fusarium spp. have been described, little is known about the genetic variability of this group, even if it can be found in countless places. Therefore, this work had the objectives of increase this knowledge, evaluating the genetic variability and modes of interaction between Fusarium spp pathogenic and non-pathogenic isolates, obtained from different hosts. In this way, ARDRA, rDNA sequencing, and RAPD techniques evaluated 83 Fusarium spp. isolates. The ARDRA analysis allowed the separation of 83 isolates in 19 haplotypes. In spite of the great diversity found inside each haplotypes, in general it was difficult to distinguish pathogenic and nonpathogenic isolates. In the sequencing analysis of the ITS region of rDNA, it was observed that Fusarium isolates were grouped together independently to the species. These results proved the need for a taxonomic review inside Fusarium genera. The RAPD analysis revealed that the 83 Fusarium spp. isolates evaluated in this study presents high levels of variability not correlated with the taxonomic characteristic. However, we observed that pathogenic and endophytical F. oxysporum isolated from soybean are genetically different. The interaction analysis between pathogenic and non-pathogenic isolates of Fusarium spp. with susceptible cultivars of tomato and soybean, showed different modes of interaction on different plant tissues, where some endophytical isolates increased plant growth. Among these, we can emphasize the endophytic isolate Cac19.4, that is genetically different if compared with Fusarium spp. pathogenic isolates, in spite of his ability to promote an increase in root and stems weight of soybean and tomato plantlets. Thus, this isolate could be selected for further analysis, looking for a better use of this endophytical microorganism in agricultural interest studies.

Mutualistic interactions between species are balanced on a delicate scale of net benefits to both interacting partners. The dynamics of such interactions could change depending on the context in which these interactions occur. One of the most well-studied models for interspecies mutualisms are myrmecophytic systems, also known as ant-plant systems, where the host plant (myrmecophyte) provides shelter (domatia), solely or along with food resources, for ant partners, while the domatia-resident ants intensively patrol and protect the host plant from herbivory. In some cases, nutrient flux has also been reported from the ant-derived debris in the domatia to the host plant. Such mutualisms are often vulnerable to exploitation by non-mutualist organisms or interlopers such as non-protective ants and other invertebrates that use the plant rewards without any returns. Since provision of domatia and food imposes costs on the host plants, the trajectory of evolution in such cases where protection is partial or absent needs investigation to understand the evolution of myrmecophytism. In this thesis, we investigate the possibility of evolution of myrmecophytism in the absence of universal protection by partner ants, using the unique semi-myrmecophyte (domatia are not expressed in all individuals of the species) Humboldtia brunonis as the study model. H. brunonis is endemic to the tropical wet evergreen forests of the Western Ghats of India. Being locally abundant in its distribution range, this plant species has also been used in characterising forest types in the Western Ghats. H. brunonis provides domatia (modified stem internodes) and food for ants in the form of extrafloral nectar (EFN) on leaves and bracts of floral buds in all individuals. Each domatium has a self-opening slit, which could have led to the domatia being accessed and inhabited by numerous ants and other non-ant invertebrates throughout its distribution range. Of these, only one ant species, Technomyrmex albipes, has been reported to be significantly protective against herbivores, and the protection received by the plant is reported to be restricted only to one site where T. albipes is most abundant. In the light of the above, the possible explanation for continued expression of rewards (domatia as well as EFN) in the absence of universal protection was investigated. Chapter 1: Introduction This chapter starts with a brief history of the concept of mutualism, evolution and maintenance of mutualism, and trophic mutualism amongst organisms in general. This is followed by a description of ant–plant mutualisms, and the various interactions that drive the interaction in such systems, with a more detailed emphasis on trophic mutualism in ant-plants, and stable isotope analysis as a technique that is used to study trophic mutualism in ant-plants. The study system, Humboldtia brunonis is introduced, and all the studies on this system preceding this current thesis are discussed in the light of findings in other ant-plant systems. Lastly, the objectives of the thesis are briefly introduced as separate chapters. Chapter 2: Context dependency of rewards and services in an Indian ant–plant interaction: southern sites favour the mutualism between plants and ants (published in Journal of Tropical Ecology) Earlier studies on the H. brunonis system have shown that there is geographic variation in the occupancy of the domatia, with domatia in the northern part of the H. brunonis range being dominantly occupied by an arboreal earthworm species, while domatia in the south are mostly occupied by ants, especially the sole protective ant T. albipes. Further, it has been reported that herbivory is significantly reduced in the presence of ants in the south. In the present study, conducted at 5 sites spanning the distribution range of H. brunonis, we observed that there is a geographic variation in various ant-related plant traits such as abundance of domatia-bearing individuals, number of nectaries per leaf, size of nectaries, and volume and composition of the EFN, with a clear north–south increasing gradient. However, strong protection mutualism was observed only at one site in the south where herbivory pressure was highest. By comparing our results with earlier findings, we show that in addition to geographic variation, there is also temporal variation in the strength of protection mutualism, and that protection mutualism in this system is context-dependent. These results provide new perspectives on the evolution of myrmecophytism. Chapter 3: Leaf expansion and foliar extrafloral nectar as defence strategies in a paleotropical ant-plant Humboldtia brunonis (Fabaceae) (a section of this chapter is submitted to Biotropica) Despite the absence of universal protection against herbivory, H. brunonis plants constitutively secrete EFN and domatia. We therefore explored other non-chemical defences in this system, and investigated possible explanations for the continued reward production. We observed rapid rate of leaf expansion during the early and most vulnerable phase of leaf phenology, and propose this as a strategy to escape herbivory. The young leaves are also subject to being infested by phloem-feeding Hemiptera, but there was seldom any case of ants tending Hemiptera for honeydew (sugary material excreted by the Hemiptera) on the plant. We analysed the sugar and amino acids compositions of EFN, honeydew and phloem sap, and found that EFN composition was much richer and more attractive (to ants) than honeydew, thereby suggesting that EFN could possibly function to distract ants from tending Hemiptera on the plant, thereby avoiding further damage to the plant. We also observed that EFN composition was much richer than phloem sap, and thereby confirmed that EFN is not mere phloem exudate; rather, our results suggests that EFN could possibly be synthesized actively in the secretory cells of the extrafloral nectary. Anatomical observations of the foliar nectaries further support the synthesis of EFN in the secretory cells of the nectary. Chapter 4: Nutritional benefits from domatia-inhabitants in an ant–plant interaction: interlopers do pay the rent (published in Functional Ecology) In this chapter, we explore how a myrmecophytic system could evolve in the absence of protection benefits from the partner ants. We investigate non-protective benefits, specifically trophic (nutrient) benefits, from the protective and non-protective ants and other invertebrates to the host plant, using stable isotope techniques. We selected three representative inhabitant species for our analysis, viz., the protective ant T. albipes, a non-protective ant Crematogaster dorhni, and the arboreal earthworm Perionyx pullus. We observed that earthworms contributed approximately 9% while protective or non-protective ants contributed approximately 17% of the nitrogen to the plant tissues nearest to the domatium. We also observed from 15N labelling experiments that that nutrients from the domatia are not restricted solely to the domatia-bearing branch but could travel to distant non-domatia bearing branches as well. This study demonstrated for the first time that non-protective ants and non-ant invertebrates that inhabit the domatia, and hitherto referred to as interlopers, could be in a trophic mutualism with the host plant, thereby proposing the possibility of trophic mutualism as a factor for the evolution and maintenance of the domatia trait in addition to or in the absence of protection mutualism. It is also possible that fitness benefits of bearing domatia, acquired via trophic mutualism, could later facilitate the establishment of a specialised ant–plant protection mutualism. Chapter 5: Structure and development of the caulinary domatia of Humboldtia brunonis In this chapter, we investigate the morphology of domatia at different ontogenetic stages in order to understand the mode of development of the domatia. Our observations show that the domatium of H. brunonis is formed spontaneously near the terminal end of a growing branch, next to the young apical shoot. It appears as a young swollen internode which is soft and fleshy with the pith tissue still present. As the domatia grows and expands, the collective effect of both schizogeny as well as lysogeny, act on on the pith region. We also observed acropetal lignification of the pith cells around the hollow chamber. We investigate micro-scale anatomy of the inner wall of the domatia using scanning electron microscopy, and observed that the inner lining of the domatia cavity have canaliculated, lignified sclerenchyma with numerous plasmodesmata (intercellular pits) that could facilitate the flow of occupant-derived nutrients supporting trophic interaction between the plant and its domatia inhabitants. We also observed fungal mycelia-like structures in ant-occupied domatia that suggests the possibility of a fungus as a third party in the ant–plant trophic mutualism, as is observed in some other myrmecophytic systems. This aspect however needs further investigation. Chapter 6: Conclusion In this chapter, the main findings of the preceding chapters are summarised. A general conclusion of the thesis is provided, and future directions leading from the present thesis are also listed. The present thesis has explored the dynamics of interactions between a unique semi-myrmecophyte and its domatia-inhabitants; while the unprotected host plant resorts to an escape strategy to evade foliar herbivory, the ants (and other invertebrates) seem to have bid “a farewell to arms” and yet maintain a mutualism with its host via nutrient exchange. The results of this thesis contribute to furthering our current understanding of the evolution and stability of inter-species mutualisms.

京都大学 / 0048 / 新制・課程博士 / 博士(人間・環境学) / 甲第18359号 / 人博第672号 / 新制||人||162(附属図書館) / 25||人博||672(吉田南総合図書館) / 31217 / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 市岡 孝朗, 教授 加藤 眞, 教授 松井 正文 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DGAM

I investigated the effects ofhabitat loss and subsequent restoration on invertebrate community structure and ecosystem functioning in a mined peat bog in the North Island, New Zealand. In an experimental trial, the impact of peat bog habitat loss and isolation on the invertebrate community associated with Sporadanthus ferrugineus (Restionaceae) was investigated. Potted S. ferrugineus plants were exposed to invertebrates at various distances up to 800 m from an intact habitat (the presumed source population) over 18 weeks. Invertebrates rapidly colonised the experimental plants, with all major Orders and trophic groups present on Sc ferrugineus within 6 weeks. However. with increasing distance away from the undisturbed habitat, there was a significant decrease in total richness and abundance of invertebrates associated with the potted plants. Additional tests showed that even a moderate degree of isolation (i.e. greater than 400 m) from the intact habitat caused an almost complete failure of 'Batrachedra' sp. to colonise its host plant, at least in the short-term, The density of eggs and larvae, and the average larval size of 'Batrachedra' sp. (Lepidoptera: Coleophoridae) colonising Si ferrugineus plants, as well as the proportion of Si ferrugineus stems damaged by 'Batrachedra' sp. herbivory, all decreased logarithmically with increasing distance from the intact habitat. Surprisingly, though, the rate of recovery of the insect-plant interaction following experimental habitat restoration was remarkably rapid (i.e. between 3Y2 and 6 years). After just 6 years there was no significant difference in insect-plant interactions between the intact peat bog sites and any of the experimentally restored sites up to 800 m away. These results suggest that the degree of isolation from undisturbed habitat has a major impact on the rate and patterns of restoration recovery in the invertebrate community and that some insect-plant interactions can recover rapidly from habitat loss with restoration management. Restoration of mined peat bogs in northern New Zealand is initiated by establishing a native vegetation cover to minimize further peat degradation. The effects of various restoration techniques on litter decomposition, microbial community activity and beetle community composition were investigated within an experimental trial, These treatments included translocation ofpeat bog habitat (direct transfer of islands), milled peat islands with no seed and milled peat islands with seed, and were compared with an unrestored mined site and an undisturbed peat bog. In all the response variables measured, the undisturbed peat bog sites had significantly higher decomposition rates and microbial respiration rates, and significantly higher abundance and species richness of beetles than any of the restoration treatments. Inaddition, the technique used to restore mined peatlands had a significant effect on the beetle community composition and litter decomposition processes. Despite a rapid initial change in the beetle community following habitat translocation, the direct transfer islands were still the most similar in beetle species composition to the undisturbed peat bog. Microbial activity and decomposition rates were higher in the direct transfer and mined peat surface after 6 months. However, even after 12 months, decomposition rates in the restored habitats were still far from reaching the levels recorded in the undisturbed peat bog. The results suggest that beetle community structure and ecosystem processes such as decomposition and microbial activity rates may be able to recover faster with certain restoration techniques, such as direct transfer of intact habitat islands. Subsequently, I examined long-term beetle community reassembly on islands that had been restored by creating raised areas ofprocessed peat with the addition of Leptospermum scoparium seed. Monitoring of different-aged restored islands representing the full range of restoration ages (up to 6 years) available at the peat mine, indicated that as the peat islands became older and the vegetation structure became more complex, the abundance, species richness and composition of the beetle community became increasingly similar to the community in the undisturbed peat bog. Despite this, distinct differences between the intact peat bog and older restored peat islands still persisted, even after 6 years, particularly at an individual species level. However, it is predicted that within 12 years the restored peat islands will share 100% ofbeetle species in common with the undisturbed peat bog. Taken together, these results indicate that restoration is effective in initiating the recovery of beetle assemblages and ecosystem processes (such as litter decomposition and microbial community activity) in cut-over peat bogs. However, it is estimated to take at least 12 years before pre-mining communities and functions are attained, and ongoing monitoring to develop an understanding of the longer-term dynamics of such ecosystems and processes is clearly required.

Plant feeding insects comprise about 25% of all animal species on earth and play an important role in all ecosystems. Although we understand that their association with plants is a key-factor driving the diversification in this group, we still have large gaps in our knowledge of the underlying processes of this relationship. Female choice of host plant is an important event in the insect life-cycle, as it is a major determinant of the larval food plant. In this Thesis I studied different aspects of insect host plant choice and used butterflies from the family Nymphalidae as my study system. I found that butterflies have a well developed olfactory system and that they use odors when searching for food or host plants. However, the information obtained from the odor of host plants does not seem to be sufficient for the studied species to make a distinction between plants of different qualities. Interestingly, even when in full contact with the leaf they do not make optimal decisions. I show for example that a sub-optimal female choice may be mitigated by larval ability to cope with unfavorable situations. Moreover, species that utilize a broader set of host plants may not be very well adapted to all the hosts they use, but at the same time they may survive in areas where there is only a subset of the plants available. Lastly, differences in the evolution of life-history traits between species can account for differences in how each species realizes its lifestyle. Thus, by incorporating findings on mechanisms of host plant choice with the ecological and evolutionary context of a species, our ability to explain the dynamics of host plant choice and insect-plant interactions can be improved. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

Os nectários extraflorais (NEFs) são estruturas produtoras de néctar, não relacionadas com a polinização, mas podem estar presentes em partes tanto vegetativas quanto reprodutivas da planta. Essas estruturas atraem uma grande diversidade de artrópodes, principalmente formigas, as quais protegem as plantas do ataque de herbívoros. Em geral, essas interações formiga-planta mediadas por NEFs são positivas, no entanto, em alguns casos podem apresentar efeitos negativos, interferindo diretamente no valor adaptativo da planta. Diante dessa perspectiva, este estudo objetivou avaliar se a atração de formigas para proteção contra o ataque de herbívoros, causa indiretamente um impacto sobre a polinização, influenciando, consequentemente, no sucesso reprodutivo de Palicourea rigida. Esta Rubiaceae é um arbusto muito comum no Cerrado, que apresenta nectários pericarpiais (NPs NEFs localizados em frutos). A principal hipótese do trabalho foi que as formigas beneficiam P. rigida, reduzindo a ação de herbívoros foliares, mas ao mesmo tempo interferem no sucesso reprodutivo da planta, pois inibem a ação dos principais polinizadores. O estudo foi desenvolvido entre novembro de 2016 e fevereiro de 2017 na reserva ecológica do Clube Caça e Pesca Itororó de Uberlândia, no município de Uberlândia, Minas Gerais, Brasil, área que apresenta como principal fitofisionomia o cerrado sentido restrito. Os resultados corroboraram a hipótese principal, demonstrando que de fato as formigas protegem a planta, reduzindo a ação de herbívoros foliares, mas que dependendo da espécie de formiga podem interferir negativamente na formação de frutos, já que inibem a ação dos principais polinizadores da planta os beija-flores. Nosso estudo revela que Palicourea rigida possui um sistema complexo de interações, envolvendo formiga-planta-polinizador, sendo esse o primeiro estudo a avaliar os custos indiretos de um mutualismo protetivo formiga-planta sobre o valor adaptativo direto (produção de frutos) em plantas polinizadas por aves. / Extrafloral nectaries (EFNs) are glands that produce nectar not related to pollination and may be present in both vegetative and reproductive plant parts. These structures attract a great diversity of arthropods, mainly ants, which protect plants from herbivorous attack. In general, ant-plant interactions mediated by EFNs are positive, however, in some cases they may have negative effects, interfering directly in plants fitness. From this perspective, our study aimed to evaluates whether the attraction of ants by an EFNs bearing plant, effectively protects the vegetable against herbivorous attack, but indirectly has anegative impact on pollination. We used as a model, Palicourea rigida (Rubiaceae), a common shrub in the Cerrado, that presents pericarpial nectaries (PNs - EFNs located in fruits). The main hypothesis of the work was that ants benefits P. rigida, reducing the action of foliar herbivores, but at the same time negatively interfere on its reproductive success by inhibiting the action of the main pollinators. The field work was developed between November 2016 and February 2017, in the ecological cerrado reserve of the Clube Caça e Pesca Itororó de Uberlândia, in Uberlândia city, Minas Gerais, Brazil. The results corroborated our main hypothesis, demonstrating that ants in fact protect the plant reducing the action of foliar herbivores and can, depending on the ant species, negatively interfere in fruit set, since they inhibit the action of the main pollinators - the hummingbirds. These results show that P. rigida has a complex system of interactions, involving ant-plant-pollinator. This is the first study to evaluate the indirect costs of ant-plant mutualism on the fruit set of a plant pollinated by birds.

Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae), também conhecida por traça-das-crucíferas, é uma praga importante de Brassicaceae, que pode ser encontrada em todos os continentes. A relação entre P. xylostella e as brassicáceas tem sido muito estudada uma vez que essa praga provoca grandes prejuízos em praticamente todas as regiões produtoras, no Brasil e no mundo. Também tem despertado grande interesse entre os pesquisadores o fato das brassicáceas utilizarem metabólicos secundários como defesa ao ataque de insetos generalistas, sendo que para especialistas, como P. xylostella, alguns desses metabólicos são incitantes de alimentação e oviposição. Na interação inseto-planta existem questões não compreendidas e que devem ser estudas, pois são diversas condições bióticas e abióticas que interagem nestes organismos, podendo promover alterações fisiológicas e nutricionais nas plantas, no desenvolvimento dos insetos e nas interações planta x herbívoro x parasitoide/predador. Assim, este trabalho objetivou estudar a influência de estresses hídricos em variedades de brássicas e seus reflexos nas plantas, no herbívoro especialista P. xylostella e no parasitoide Trichogramma pretiosum (Riley, 1879) (Hymenoptera: Trichogrammatidae). Foram efetuadas análises da composição química em folhas e da emissão de voláteis em três variedades (couve - Brassica oleracea var. acephala; brócolis - B. oleracea var. italica e repolho - B. oleracea var. capitata), em diferentes níveis de água no solo (50%, 70% e 100% da capacidade de campo), procurando-se determinar plantas comprovadamente com estresse hídrico. Também foi estudada a influência daquelas condições hídridas em parâmetros biológicos de desenvolvimento, de reprodução e de comportamento de P. xylostella, além da influência dos estresses hídricos na atratividade/repelência de T. pretiosum, parasitoide de ovos de P. xylostella. Com as variedades desenvolvidas nas três condições hídricas foram determinados: (a) nas plantas/folhas: taxa de peroxidação lipídica (MDA), porcentagem de proteína bruta na matéria seca, fibra em detergente neutro, fibra em detergente ácido, hemicelulose, lipídeos, teor de cera, proteínas insolúveis em detergente neutro, proteínas insolúveis em detergente ácido, proteínas disponíveis, matéria mineral, carboidratos totais e a emissão de voláteis; (b) com P. xylostella: consumo foliar, período larval, viabilidade larval, período pupal, viabilidade pupal, peso de pupas, razão sexual, ovos por fêmea, viabilidade de ovos, longevidade de fêmeas, longevidade de machos e tabela de vida de fertilidade, em laboratório e casa de vegetação, além da preferência para oviposição em testes com e sem chance de escolha; e (c) com T. pretiosum: teste de olfatometria com plantas nas três condições hídricas. Os resultados obtidos permitem concluir que: o déficit hídrico provoca estresse em couve, brócolis e repolho e em maior intensidade nas plantas cultivadas com menor quantidade de água disponível no solo; quantitativamente, a composição química das plantas (couve, brócolis e repolho) é alterada em função do estresse hídrico, principalmente quanto à proteína bruta e disponível, hemicelulose, lipídeos, proteínas ligadas à fibra em detergente ácido e neutro, matéria mineral e carboidratos totais; os parâmetros de desenvolvimento de P. xylostella são alterados, tanto em laboratório como em casa de vegetação, com as lagartas alimentando-se das plantas cultivadas nas diferentes condições hídricas de solo, refletindo significativamente na capacidade reprodutiva e na sobrevivência dos insetos; o estresse hídrico altera a emissão de voláteis em plantas de couve, em brócolis e repolho; a preferência de P. xylostella para oviposição, em testes com chance e sem chance, é influenciada pelo estresse hídrico em couve, brócolis e repolho; os testes de olfatometria mostram que o estresse hídrico influencia na escolha de T. pretiosum para oviposição, mais expressivamente em plantas com maiores índices de estresse hídrico / Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae), also known as cruciferous moth, is an important pest of Brassicaceae, which can be found on all continents. The relationship between P. xylostella and brassicaceae has been much studied since this pest causes great damages in practically all the producing regions, in Brazil and in the world. It has also aroused great interest among researchers that brassicaceae use secondary metabolites as a defense against the attack of generalist insects, and for specialists, such as P. xylostella, some of these metabolites are prompting feeding and oviposition. In the interaction insect-plant there are questions not understood and that must be studied, because several biotic and abiotic conditions interact in these organisms, being able to promote physiological and nutritional changes in plants, in the development of insects and in the interactions plant x herbivore x parasitoid / predator. The objective of this work was to study the influence of water stresses on brassic varieties and their reflexes on plants, the P. xylostella herbivore and the Trichogramma pretiosum (Riley, 1879) (Hymenoptera: Trichogrammatidae) parasitoid. The chemical composition of leaves and the volatile emission were evaluated in three different varieties (kale - Brassica oleracea var. acephala; broccoli - B. oleracea var. italica and cabbage - B. oleracea var. capitata) in different soil water levels (50%, 70% and 100% of the field capacity), aiming to determine plants with water stress. The influence of these water conditions on biological development, reproduction and behavioral of P. xylostella, as well as the influence of water stress on the attractiveness / repellency of T. pretiosum parasitoid on P. xylostella eggs. The three varieties grown in the three water conditions and were determined: (a) in the plants / leaves: lipid peroxidation rate (MDA), percentage of crude protein in dry matter, neutral detergent fiber, acid detergent fiber, hemicellulose, lipids, wax, neutral detergent insoluble proteins, acid detergent insoluble proteins, available proteins, mineral matter, total carbohydrates and the emission of volatiles; (b) with P. xylostella: leaf consumption, larval period, larval viability, pupal period, pupal viability, pupal weight, sex ratio, eggs per female, egg viability, female longevity, male longevity and life table of fertility, laboratory and greenhouse, in addition to the preference for oviposition in tests with and without a choice; and (c) with T. pretiosum: tests of olfactometry with plants in the three water conditions. The results obtained allow us to conclude that: the water deficit causes stress in kale, broccoli and cabbage and in higher intensity in the plants cultivated with less amount of water available in the soil; quantitatively, the chemical composition of the plants (kale, broccoli and cabbage) is altered as a function of water stress, mainly as regards crude and available protein, hemicellulose, lipids, acid and neutral detergent fiber binding proteins, mineral matter and total carbohydrates; the development parameters of P. xylostella are altered, both in the laboratory and in the greenhouse, with caterpillars feeding on plants grown under different soil water conditions, significantly reflecting the reproductive capacity and survival of the insects; water stress changes the emission of volatiles in kale, broccoli and cabbage plants; the preference of P. xylostella for oviposition, in tests with chance and without chance, is influenced by water stress in kale, broccoli and cabbage; olfactometry tests show that water stress influences the choice of T. pretiosum for oviposition, more expressively in plants with higher rates of water stress